ADA4938-2ACPZ-R7 datasheet(18/26 Pages) AD

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ADA4938-1/ADA4938-2

Data Sheet

Rev. B | Page 18 of 26

TERMINOLOGY

ADA4938

+IN

–IN

+OUT

–OUT

–FB

+FB

VOCM

VOUT, dm

RL, dm

Figure 57. Circuit Definitions

Differential Voltage

The differential voltage is the difference between two node

voltages. For example, the output differential voltage (or

equivalently, output differential-mode voltage) is defined as

VOUT, dm = (V+OUT − V−OUT)

where V+OUT and V−OUT refer to the voltages at the +OUT and

−OUT terminals with respect to a common reference.

Common-Mode Voltage

The common-mode voltage is the average of two node voltages.

The output common-mode voltage is defined as

VOUT, cm = (V+OUT + V−OUT)/2

Balance

Balance is a measure of how well differential signals are matched in

amplitude and are exactly 180° apart in phase. Balance is most

easily determined by placing a well-matched resistor divider

between the differential voltage nodes and comparing the

magnitude of the signal at the midpoint of the divider with

the magnitude of the differential signal. By this definition,

output balance is the magnitude of the output common-mode

voltage divided by the magnitude of the output differential

mode voltage.

OUT

Error

Balance

Output

ADA4938-2ACPZ-R7 Datasheet(PDF) 18 Page - Analog Devices